package main

import "fmt"

func add(x, y int) (sum int) {
	return x + y
}

func swap(x, y int) (int, int) {
	return y, x
}

func main() {
	z := add(1, 2)
	fmt.Printf("z = %d\n", z)

	x := 10
	y := 20
	fmt.Printf("x=%d, y=%d\n", x, y)
	x, y = swap(x, y)
	fmt.Printf("x=%d, y=%d\n", x, y)
	fmt.Printf("z = %d\n", add(swap(x, y)))
}
